1. Field of the Invention
This invention relates to the field of workpiece centering devices and more particularly to a novel center locator incorporating optical or electro-mechanical components adapted to register with target elements carried on the workpiece whereby exact centering of the workpiece is achieved with respect to a cutting tool.
2. Brief Description of the Prior Art
In the past, it has been difficult to accurately locate the center of a workpiece intended to be worked on by a cutting tool. For example, when it is desired to drill a hole in a workpiece, the workpiece is held by a holder underneath a drill press and the cutting tool, such as a drill, is lowered into cutting relationship with the workpiece. It is imperative that the cutting tool be properly aligned with the workpiece so that the point of the drill is aligned on the center axis of the workpiece hole which is intended to be drilled.
A dial indicator is used with a rod in rotation to the chuck or spindle. The indicator uses a quill for sweeping the wall of the hole. The table or work is moved in X and Y directions until the indicator reaches "0" or null.
Some attempts have been made to provide a center locator device which may be referred to as a "plumb-type" wherein a weighted object is carried on the end of a line or wire so that gravity positions the weighted device directly over the workpiece for center location. Such devices are operable for their intended purpose; however, difficulties and problems have been encountered with such devices that stem largely from the fact that the string or wire cannot be accurately located at the point of the cutting tool so that the exact center on the workpiece can be located. Usually, the string or wire is attached off to one side whereby the center is offset from that which is actually desired. The offset tends to confuse the workmen and inaccurately cut workpieces result. Thus, inefficiency waste and loss of time and material results from the use of conventional plumb-type center locators. Such locators are acceptable for construction and building fields such as in the construction and building field, but where accuracy and precision is required, such devices are totally inadequate.
Therefore, a long standing need has existed to provide an accurate center locator which may be rapidly attached to a tool for locating the center of a workpiece.